pith (n.) Look up pith at Dictionary.com
Old English piþa "pith of plants," also "essential part," from West Germanic *pithan- (cognates: Middle Dutch pitte, Dutch pit, East Frisian pit), a Low German root of uncertain origin. Figurative sense was in Old English. Pith helmet (1889, earlier pith hat, 1884) so called because it is made from the dried pith of the Bengal spongewood.
pith (v.) Look up pith at Dictionary.com
"to kill by piercing the spinal cord," 1805, from pith (n.). Related: Pithed; pithing.